Calculating discounted future return for agent

discounted_future_return.py

''' Gets list of furture rewards, associates discount factor with future rewards '''
def discounted_future_return(rewards, gamma=0.98):
    discounted_returns = [0 for _ in rewards]
    discounted_returns[-1] = rewards[-1]
    for t in range(len(rewards) - 2. -1, -1):
        discounted_returns[t] = rewards[t] + gamma * discounted_returns[t+1]
    return discounted_returns